Machines, for example backhoes, excavators, graders, and loaders, commonly have linkage that is movable to control the motion of a connected implement such as a bucket, a blade, a hammer, a grapple and the like. When equipped with a single implement, these machines become specialized machines that are primarily used for a single purpose. Although adequate for some situations, the single purpose machines can have limited functionality and versatility. An implement coupler assembly can be used to increase the functionality and versatility of a host machine by allowing different implements to be quickly and interchangeably connected to the linkage of the machine.
Implement coupler assemblies are generally known and include a frame connected to the linkage of a machine, and hooks, latches, wedges, pins and the like that protrude from the frame. The hooks of an implement coupler assembly engage corresponding pins of an implement to thereby connect the implement to the linkage. To help prevent undesired disengagement of the hooks from the pins, implement coupler assemblies can be equipped with a hydraulic cylinder that locks the hooks in place against the pins.
When connecting or disconnecting an implement to a host machine, precautions should be taken to help ensure the procedure is performed properly. For example, the implement should be in a desired resting position before decoupling is performed so that the implement does not move in an unexpected manner after the decoupling. In addition, fluid provided to the hydraulic cylinder of the implement coupler assembly should be at a pressure that allows proper operation of the implement coupler assembly without causing damage to the assembly.
One example of an implement coupler assembly is disclosed in U.S. Pat. No. 8,281,506 issued to Stefek et al. on Oct. 9, 2012. The Stefek et al. patent discloses an implement coupler assembly for a machine. The implement coupler assembly may have a coupler frame, a first latch, a second latch, and a hydraulic actuator or cylinder connected to move the second latch relative to the first latch and the coupler frame. The hydraulic cylinder may have a first chamber, a second chamber, and a pressure valve with a check element movable to allow a flow of fluid into the first chamber based on a pressure of fluid in the first chamber, and a pressure regulating element movable to allow a flow of fluid out of the first chamber based on a pressure of fluid in the second chamber. The implement coupler assembly may additionally have a first pilot passage configured to communicate fluid from the second chamber with the pressure regulating element, and a second pilot passage configured to communicate fluid from the first chamber with the pressure regulating element. The hydraulic cylinder of the implement coupler assembly receives pressurized fluid from a first chamber of an implement hydraulic cylinder that controls the position of the implement attached to the coupler assembly. The pressure in the implement cylinder maintains the pressure in the coupler cylinder. The implement coupler assembly is effective in coupling and decoupling the implement, but opportunities may still exist for further improvements to the technology.